The prior art has accomplished such control by a system of time multiplex, or in a fragmentary way by a scheme of self-assigning address.
The U.S. Pat. No. 3,795,771, of Mar. 5, 1974 to J. Gundersen et al is one example of multiplexing; the example given therein pertaining to attendant service and entertainment for each passenger in a large jet aircraft.
MOS-FET integrated circuit chips are employed and the circuitry includes numerous counters, flip-flops, shift registers, and AND, NAND and NOR gates.
The U.S. Pat. No. 3,585,595, of June 15, 1971 to M. Slavin et al is another example, having a closed loop with series-connected coders. In a sequence, coders and decoders are sequentially activated to perform their assigned functions. Thereafter, each activated coder and decoder assumes an inactive state, in which they permit the passage of control signals and data therethrough. The control signals can be applied in either direction along the series connections.
The U.S. Pat. No. 4,253,087, of Feb. 24, 1981, to H. Saal is an example of self-assigning address. However, it discloses an address system only, having one series of addressable units connected to one control unit. Use circuits are not disclosed at all. Each addressable unit has a signaling device, such as an electronic circuit, which operates in the same manner at each addressable unit location by permuting signals appearing on the input connector.
The control unit emits several "signals" in two prime-related groups. The simultaneous appearance of these several signals at only one device accomplishes the addressing. The nature of, and the waveshapes of, the signals are not disclosed.